From 4a2dcb224626b5c57bc39f19b3c99dfde9925173 Mon Sep 17 00:00:00 2001
From: Scott Stevenson <scott@stevenson.io>
Date: Tue, 21 Nov 2017 15:10:07 +0000
Subject: [PATCH 1/5] Add SU and SD constants to pyte.escape

---
 pyte/escape.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pyte/escape.py b/pyte/escape.py
index dc06b8b..1564fb1 100644
--- a/pyte/escape.py
+++ b/pyte/escape.py
@@ -152,3 +152,9 @@
 
 #: *Horizontal position adjust*: Same as :data:`CHA`.
 HPA = "'"
+
+#: *Scroll up*
+SU = "S"
+
+#: *Scroll down*
+SD = "T"

From 1da5b4a2b8a0f1549e12bbc33eaa416dd8aee9b7 Mon Sep 17 00:00:00 2001
From: Scott Stevenson <scott@stevenson.io>
Date: Tue, 21 Nov 2017 15:11:03 +0000
Subject: [PATCH 2/5] Add scroll_down and scroll_up entries to csi dict

---
 pyte/streams.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/pyte/streams.py b/pyte/streams.py
index 6d684f6..7bbcc3e 100644
--- a/pyte/streams.py
+++ b/pyte/streams.py
@@ -117,7 +117,9 @@ class Stream(object):
         esc.SGR: "select_graphic_rendition",
         esc.DSR: "report_device_status",
         esc.DECSTBM: "set_margins",
-        esc.HPA: "cursor_to_column"
+        esc.HPA: "cursor_to_column",
+        esc.SD: "scroll_down",
+        esc.SU: "scroll_up"
     }
 
     #: A set of all events dispatched by the stream.

From f15ea30d05490e38648c4d94424de1bb1518ff7d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADctor=20Zabalza?= <vzabalza@gmail.com>
Date: Tue, 21 Nov 2017 16:47:38 +0000
Subject: [PATCH 3/5] Override copy method so that StaticDefaultDict does not
 return a regular dict

---
 pyte/screens.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pyte/screens.py b/pyte/screens.py
index a297092..52b4110 100644
--- a/pyte/screens.py
+++ b/pyte/screens.py
@@ -139,6 +139,11 @@ def __init__(self, default):
     def __missing__(self, key):
         return self.default
 
+    def copy(self):
+        new_static_default_dict = type(self)(self.default)
+        new_static_default_dict.update(self)
+        return new_static_default_dict
+
 
 class Screen(object):
     """

From 97843a05c1d5da541c9f850f073a4f25a75019cf Mon Sep 17 00:00:00 2001
From: Scott Stevenson <scott@stevenson.io>
Date: Tue, 21 Nov 2017 15:12:18 +0000
Subject: [PATCH 4/5] Implement Screen.scroll_down and Screen.scroll_up

---
 pyte/screens.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/pyte/screens.py b/pyte/screens.py
index 52b4110..0b45f27 100644
--- a/pyte/screens.py
+++ b/pyte/screens.py
@@ -1048,6 +1048,26 @@ def debug(self, *args, **kwargs):
         By default is a noop.
         """
 
+    def scroll_up(self, lines):
+        """Scroll up `lines` lines."""
+        lines_to_scroll = range(self.margins.top, self.margins.bottom + 1)
+        for y in lines_to_scroll:
+            if y + lines in set(lines_to_scroll):
+                self.buffer[y] = self.buffer[y + lines].copy()
+            else:
+                self.buffer[y].clear()
+        self.dirty = set(lines_to_scroll)
+
+    def scroll_down(self, lines):
+        """Scroll down `lines` lines."""
+        lines_to_scroll = range(self.margins.bottom, self.margins.top - 1, -1)
+        for y in lines_to_scroll:
+            if y - lines in set(lines_to_scroll):
+                self.buffer[y] = self.buffer[y - lines].copy()
+            else:
+                self.buffer[y].clear()
+        self.dirty = set(lines_to_scroll)
+
 
 class DiffScreen(Screen):
     """

From 2e86d5d7dcb98b4bd3bd70e86739275ca2dbcc2e Mon Sep 17 00:00:00 2001
From: Scott Stevenson <scott@stevenson.io>
Date: Tue, 21 Nov 2017 16:00:37 +0000
Subject: [PATCH 5/5] Test Screen.scroll_down and Screen.scroll_up

---
 tests/test_screen.py | 51 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/tests/test_screen.py b/tests/test_screen.py
index b171b5e..b7481c5 100644
--- a/tests/test_screen.py
+++ b/tests/test_screen.py
@@ -1505,3 +1505,54 @@ def test_screen_set_icon_name_title():
 
     screen.set_title(text)
     assert screen.title == text
+
+
+def test_scroll_down():
+    screen = pyte.Screen(1, 5)
+    screen.set_mode(mo.LNM)
+    screen.linefeed()
+    for i in "abcd":
+        screen.draw(i)
+        screen.linefeed()
+    screen.draw("e")
+
+    screen.set_margins(top=2, bottom=4)
+
+    assert screen.display == ["a",
+                              "b",
+                              "c",
+                              "d",
+                              "e"]
+
+    screen.scroll_down(2)
+
+    assert screen.display == ["a",
+                              " ",
+                              " ",
+                              "b",
+                              "e"]
+
+def test_scroll_up():
+    screen = pyte.Screen(1, 5)
+    screen.set_mode(mo.LNM)
+    screen.linefeed()
+    for i in "abcd":
+        screen.draw(i)
+        screen.linefeed()
+    screen.draw("e")
+
+    screen.set_margins(top=2, bottom=4)
+
+    assert screen.display == ["a",
+                              "b",
+                              "c",
+                              "d",
+                              "e"]
+
+    screen.scroll_up(2)
+
+    assert screen.display == ["a",
+                              "d",
+                              " ",
+                              " ",
+                              "e"]